WASHINGTON -- The Pentagon today admitted that airstrikes aren't enough to keep the Syrian border city of Kobane from falling to ISIS, but acknowledged it hadn't yet even selected which opposition fighters to train to lead a ground campaign against the Islamic State.

ISIS supporters tweeted tonight that Kobane, a largely evacuated city of 400,000 with thousands left to be potentially massacred by the terrorists, was completely in their hands. Kurdish sources disputed that, saying their YPG fighters were still hanging in but being pushed back by the ISIS advance.

The location of the city, so close to the Turkish border that Kurds have been able to watch fighting from the hills of the Republic, gives ISIS a strategic border crossing at a NATO country.

"We've been saying since the very beginning that airstrikes alone are not going to be sufficient," Pentagon press secretary Rear Adm. John Kirby told reporters in a noontime exchange. "...Efficiency and effectiveness are completely two different things, at least in a military mind. We believe they have been effective at what they are trying to achieve."

Kirby maintained that the mission is to support Iraqi and Kurdish ground forces "as they take the fight to ISIL on the ground inside their country."

"So in Syria, the airstrikes are principally designed and -- and many of the strikes that we've taken -- even as recently as a couple of days ago -- are against fixed targets, facilities, ways in which they are using to headquarters themselves, sustain themselves, train."

But the airstrikes -- six overnight in and around the city -- are "not going to save the town of Kobane."

"We know that. And we've been saying that over and over again. And yet we continue to get questions of, well, why aren't you doing more? And how come they aren't more effective?" Kirby continued. "...And we don't have a willing, capable, effective partner on the ground inside Syria right now. It's just a fact. I can't change that."

"…Everybody's focused on this town of Kobane, and I get that. But there's still a lot of fighting going on inside Iraq. These guys have not given up a whole heck of a lot of ground inside Iraq."

The Pentagon spokesman said they're "eager" to get the training program, which will take place on Saudi Arabian soil, off the ground, but it's no-go yet. "There's been no vetting started yet and no recruiting at this point. We are in the very early stages right now of trying to develop the procedures and protocols within which we would do that," he said, adding that they're also "sizing up the facility" with the Saudis and looking at three to five months until any training can even begin.

And despite the threat to Kobane, it's not a fall that will spur the Defense Department to recommend ground forces.

"I think we all understand that that's a possibility, that Kobane could be taken. We recognize that. We're doing everything we can from the air to try to halt the momentum of ISIL against that town, but that airpower is not going to be alone enough to save that city."

But, Kirby argued, "it's not just about Kobane."

"What I'm telling you is, rather than say what we're not going to do, let me tell you what we are going to do, and that's to take a regional approach here," he said. "So it's easy to get fixated on one town, but I think it's really important for you and for the American people to take a couple of steps back here and look at the larger regional context within which this fight is being made. And the longer-term strategic objectives that we and our coalition members are trying to apply here."